Hi agonda1
The valve clearances depend on the year and model / + which cam is fitted
Klaus posted the correct proceedure,
Have you checked the timing on
both cylinders? Reconditioned mags need checking too
What non standard exhausts are fitted?
Have you removed the baffles and tried the bike?
Either a very lean mixture on the rh cyl ?? doubtful by black plugs??
retarded timing on that side?
or unburned fuel igniting in the exhaust??
Air leak due to loose valve guide ??
Is there any obstruction in the inlet tract?? gasket or drip tray??
HTH
John